Conditional Reflex
by MsMattJeevas
Summary: Matt is finally back with Mello but he's ignoring him. However, it seems that Mello's childhood experiment, based off Pavlov's dogs, can get Matt's attention directed at him with a mere whistle. MXM AND ALL COMPLETELY SMEXY LEMON!


**Got this idea a while back, and it just made me laugh cause the concept of it was so hilariously funny and I could completely make it into a lemon.**

**Plus, I got so many good reviews from my first lemon **_**Handcuffed**_** I figured I should write another one, to appease the readers.**

**So, for my second lemon, this ended up a lot longer than I thought it would be. However, it's all smexy lemon so I'm sure you'll forgive me for the length. XD**

**" ~.~ " are breaks this time.  
**

**Genre: Romance/Humor**

**Characters: MattxMello**

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Mello was pissed.

Sure, he normally was; but this time he was pissed at Matt. He had called Matt to come help him, and it was the first contact they'd had in years. Mello hadn't seen Matt since he snuck out of Whammy's, leaving behind Matt, who had been asleep, N64 controller still in hand.

To the point, Matt had arrived yesterday at Mello's doorstep, goggles secured over his eyes, cigarette hanging from his lips, and bags of gaming equipment with him. Mello had given him until today to sort out his new living arrangement, and was now expecting Matt to be all over him, just like how he used to be.

Before Mello had left, he and Matt definitely had had something. More than something if you counted the numerous time they'd had sex. Matt was always following Mello around like a puppy; obeying his orders, cuddling with him, basking in his glory...

Because of this, Mello expected Matt to fall right back into that now that they were together again; however, that was not the case.

Currently, Matt was lounged on the couch, shooting down enemies on Halo, and ultimately ignoring Mello.

The blonde stared at the back of Matt's head from his position against the wall behind him. Grown mafia men flinched when Mello stared at them from behind; so why didn't it affect him?

Mello was about to give up for the time being to find some chocolate when a thought came to mind. A thought that made Mello _very_ curious.

He crept up to the couch, silent as a panther, and leaned his mouth down to where Matt's left ear was slightly exposed through the red mop of hair. He watched the boy closely as he let out a low whistle, the air blowing into Matt's ear.

The controller dropped from Matt's fingers, game totally forgotten, and an intense moan escaped from his lips. Mello was extremely pleased by the immediate painful tightening of Matt's pants, and by his quickened breaths. He smirked at the predicted effect that it had on the boy.

And it was all thanks to the psychology class at Whammy's that Matt didn't take with him.

~.~

It all started when Mello was introduced to the concept of conditional reflex. A man named Pavlov experimented with this concept using dogs as his subjects. He found that as he got the dogs their food, they would salivate. So, he began to ring a bell before he fed them. After a while, it got to the point where he could just ring the bell and the dogs would salivate, food or no food.

It was this, combined with the fact that Mello partially saw Matt as a puppy, that he decided to try his own experiment.

At this point, Mello and Matt had established their relationship and were exploring the wonders of physical stimulation. So, Mello began his experiment that very night.

Matt was playing his DS while laying on his bed, head hanging off the edge, and still effectively beating Mario although he was upside down and all the blood was rushing to his head.

Mello crawled onto the bed, straddling Matt's hips and laying himself down on Matt's chest.  
Matt grunted, but continued on playing despite the decreased ability to breathe.

"Matty," Mello murmured. "Come play with me." He emphasized the point by grinding their hips together in a slow rhythm.

Mello was rewarded by a hitch in Matt's breath; his fingers slowing as his eyelids drooped halfway in pleasure. However, he just kept playing, teasing Mello to see what he would do next to get him to stop.

It was a challenge that Mello accepted in an instant.

Matt was slightly surprised when Mello got up off of him, thinking it was strange that Mello decided to leave him alone.

That was, until Mello grabbed a hold of his ankles and yanked him fully onto the bed, Mello's hands sliding up Matt's body as he climbed back onto him. This time, he sat upright on top of Matt's hips, making sure Matt was watching as he slowly pulled his shirt up and over his head, exposing his creamy white flesh.

He was pleased when Matt's eyes kept darting back to him as he tried, with difficulty, to beat a boss that usually took him no effort at all.

Next, Mello's hands crept to the hem of Matt's shirt, sliding it upwards to his arm pits where he left it, satisfied with just having the hardening nubs on Matt's chest exposed. His tongue flicked out to give one rose bud a lick, circling it and nudging it playfully.

Matt stifled a moan, trying to keep his eyes open and focused on his game instead of on the blonde that was now nipping and suckling at the sensitive nub.

Satisfied with the state he was getting Matt into, he moved to the other nub, his hand creeping down to Matt's pants and undoing the button and zipper.

"Shit," Matt gasped, stiffening when he felt Mello's hand grasp him with only the thin fabric of his boxers keeping skin from meeting skin. He couldn't help the moan that escaped as Mello's fingers began moving up and down his length, coaxing it to it's full hardened state.

Mello watched Matt's face and saw the moment he gave in; the moment his eyes glazed over, and his fingers stopped moving. He reached up and plucked the game from the redhead's fingers, tossing it gently onto the other bed in the room.

"I knew you'd give into me," Mello said slyly as he licked his way up Matt's chest, pushing the shirt off all of the way and letting it drop off the side of the bed.

"Cocky bastard." However, Matt's pleasured tone didn't quite match the death glare he sent Mello.

Matt was panting now, seeing as Mello's hand had not once stopped it's ministrations, and Mello couldn't resist kissing the full lips before him. Matt's hands moved to wrap around Mello's neck, pulling them closer to each other.

Mello let his tongue flick out to lick Matt's bottom lip, but instead of being let in, Matt kept his lips tightly shut, trying to continue the game of 'see what Mello will do to make me listen'.

Another challenge that Mello took in stride, easily winning as he slipped his fingers under Matt's boxers and gripped his cock fully, continuing to stroke it with increasing speed.

This caused Matt to let out an intense moan and Mello took full advantage of the open mouth, to shove his tongue down Matt's throat. Their tongues tangled, mouths moving in sync, moans being swallowed in the process.

Mello's pants were suddenly too tight and his only thought was to get rid of the problem. He ignored Matt's whine of protest as he withdrew his hand to push his own pants and boxers off. Then he did the same with the remainder of Matt's clothes.

When he lay down on top of Matt again, their crotches pressed together creating a feeling of pleasure that had both moaning and grinding into each other to increase the delicious friction.

Their lips crashed together again, but soon it was too hard to continue because they both couldn't catch enough breath. Instead, Mello listened to Matt's sighs of pleasure as he kissed his way across his jaw, and down his neck where he proceeded to nip and suck at the flesh until a purple mark blossomed on the flushed skin.

It was the increased pitch of Matt's moans that signaled Mello to their impending climaxes, and also reminded Mello of the purpose of this whole situation.

He was trying to condition Matt.

So, slowly, not drawing attention to the act, Mello moved his lips up to Matt's ear and nipped at the lobe until he felt Matt's muscles clench, and then he let out a low whistle, the air blowing into Matt's ear.

At that moment, Matt cried out, spilling his seed onto their chests and thrusting up at Mello, sending him over the edge into his own climax.

~.~

For the numerous times after that, that they gave each other pleasure, either in the same way, or later on, with actual intercourse, Mello repeated the low whistle every time before Matt climaxed.

Because of the drunken pleasured state that he was always in, he never registered the oddness of what Mello was doing, he just took it in stride and it even heightened his pleasure after a while.

Unfortunately, L's death caught Mello off guard, and it forced him to leave Whammy's. The worst part about leaving years before he should have; besides leaving Matt behind, was that he never got to see if his experiment worked. He never got to try the whistle on Matt without touching him first.

He'd have to try it later if he ever met up with Matt again in the future. And hopefully, the conditioning stuck until then, even if Matt went years without it.

~.~

And thus, Mello was extremely pleased by the fact that even though it had been five years; the conditional reflex that Mello implanted in Matt's brain had stayed.

It looked like things were finally looking up for Mello. That is, until he was caught off guard by Matt suddenly turning his head to capture Mello's lips.

A gloved hand grabbed Mello's arm and pulled him over the back of the couch and into the gamers lap where his lips were thoroughly abused by Matt's.

"I don't know how... you did that," Matt panted as he pulled back, "but now you have to... suffer the con... sequences of making me lose my game."

Mello's breath hitched. This wasn't exactly what he expected, seeing as he was always the dominant one before; but Matt's cockiness stirred up something inside of him that made Mello feel like he wouldn't mind so much if the redhead topped him.

Matt's fingers found the zipper of Mello's leather vest and pulled it down, exposing the toned chest beneath it. He brushed his fingers over the little nubs there on his way down to the laces of Mello's leather pants. The redhead made quick work of them and was soon yanking them off the blond, pleased with the fact that Mello went commando in them.

The vest was also pulled off, as with his own striped shirt. Mello's fingers went to Matt's pants, but only got the belt and button undone before Matt pushed him away, lying him down on the couch.

Mello watched as Matt's head descended to between his thighs. He gasped as his manhood was engulfed in the warm wetness that was Matt's mouth.

Matt's tongue licked around the shaft as he moved up and down the length, and Mello's hands automatically moved to tangle in Matt's red locks, urging him on.

Gasps and moans filled the air as Mello neared his climax. Matt choosing that moment to swallow Mello deeper, deep-throating him and effectively pushing Mello over the edge; his cum shooting down Matt's throat.

The redhead swallowed as he pulled back, surveying the disheveled mess that Mello was. His hair stuck with sweat to his forehead, his chest heaving, his slowly re-hardening cock dripping with a few remains that Matt couldn't swallow.

Matt didn't think he'd ever seen Mello looking so sexy, and his manhood pulsed painfully, making him aware that his own need had been ignored in the process of satisfying Mello. The blond noticed this as well, and crawled over, about to take hold of Matt's shaft.

However, Matt stopped him with a lustful gaze. "Turn around," he ordered.

Mello did as told, staying on his hands and knees, his backside facing Matt. He didn't really mind that Matt wanted to get straight to the sex, but he had kind of wanted to taste Matt again, just like old times.

A yelp escaped Mello's lips as his hips were pulled suddenly, scooting him backwards so his arms and legs were on either side of Matt's body. His toned ass in Matt's face, and his own lips at Matt's manhood. An interesting position that they had never tried before.

Mello, wasted no time before starting to lick at the hardened member, making sure to get every inch of it before wrapping his lips around the tip, sucking gently.

Matt groaned, relishing in the pleasure he was finally at the receiving end of. However, he had his own job to do and gently pulled to lower Mello's hips to a workable angle.

He kneaded the two mounds of flesh before pulling them apart to find the tight hole that was awaiting him. Matt leaned in and flicked his tongue out to give it an experimental lick. He was delighted by Mello's shudder, and how the little hole twitched.

A small moan escaped the blond from the unexpected lick, and he moved his lips down to take more of Matt's length in his mouth, slowly moving up and down.

Then, the redhead took the plunge, and shoved his tongue passed the tight ring of muscle, moving it around and coating the inside with saliva.

Mello groaned at the wonderful new feeling of the hot muscle inside of him, picking up his speed on Matt as encouragement.

He caught the signal and pulled back to wet three of his fingers, coating them until they were dripping in saliva. Then he pushed one into Mello, working it in and out slowly.

Mello moaned around Matt's shaft, reveling in how deep Matt's finger could reach. Unfortunately he felt that it wasn't quite enough, and whined, pushing back on the finger.

A smirk formed on Matt's face, and he pushed in another finger, scissoring them to stretch Mello out, otherwise Matt would never fit. He wouldn't brag, but Matt was definitely bigger than most, and Mello's tight virgin hole would probably tear if Matt didn't stretch it out first.

On a different note, Mello was loving the feeling of being stretched, it was a kind of painful pleasure. Because of this, he was having troubles keeping his rhythm on Matt steady, his breath growing short, and his need for more pleasure growing greater.

When Matt's third finger was inserted, Mello's body curled in on itself in pain, ultimately pushing Mello's mouth further down Matt's cock which brushed the back of Mello's throat, and pushing the fingers further in.

Mello choked slightly, pushing himself off Matt so he could send a pained look back at the redhead as the fingers continued moving in and out of him, stretching him more and more.

Matt grunted, thrusting his hips up at Mello. "Keep going," he demanded in a husky voice.

Matt's cock was again engulfed by Mello, and Matt continued working his fingers inside of Mello.

The blond pulled back to lick the precum off of the tip of Matt's cock when his head was thrown back in ecstasy by an intense feeling of pleasure that jolted through him. "Matt!"

Matt's fingers were squeezed as he rubbed them against Mello's prostate. He pumped them a few more times before pulling them out, not able to resist the urge to thrust into Mello any longer.

Mello whimpered at the loss of contact as he was turned, and put down on his back again. His legs were placed onto Matt's shoulders as the redhead positioned himself.

"Just relax," Matt murmured soothingly, pushing the head of his member passed the ring of muscle.

They both sucked in a breath as Matt pushed farther in; Matt being squeezed so tight, and Mello being stretched by such a huge hot muscle.

Matt knew they wouldn't get anywhere at this pace, and thrust the rest of the way in. A pained gasp ripped from Mello's throat, his eyes squeezing shut and a tear escaping down the side of his face.

He sent a glare at Matt from behind hooded eyes. "Don't you dare fucking move!" he choked.

As hard as it was not to pound into the tight heat, Matt resisted until Mello gave a small nod to start.

He began at a slow pace, allowing Mello to adjust to the feeling of it, then he switched angle and thrust right into Mello's prostate.

"Ahh!" Mello screamed. "Right there! More...please!"

The sight of the pleading blond was the breaking point for Matt and he pounded into him mercilessly, hitting his prostate dead on each time.

Mello's legs slipped of Matt's shoulders with all the motion and were wrapped around his back instead as Matt leaned forward to kiss Mello.

Their mouths moved in desperation, both males awaiting their impending release. Tongues tangled in a battle over dominance which was easily won by Matt who thoroughly explored Mello's mouth before pulling back for a breath.

Mello's voice filled the air as he voiced his pleasure, no longer being swallowed up by Matt who trailed his kisses down to Mello's neck instead. His fingers moved to squeeze and play with Mello's nipples as he left numerous kiss marks along the nape of Mello's neck.

A coiling sensation filled Matt and he moved to grab Mello's length, jerking him off in time with his thrusts.

After a few more seconds they both released; Mello coating Matt's hand in a sticky mess, Matt filling Mello with his seed, and both yelling each others names in climax.

When the pleasured fog cleared from Matt's head, he registered the lusty look that still graced Mello's features. The blond was panting like no tomorrow, but his member was almost at attention again for the third time. Matt had never seen the blond so needy, but he wasn't complaining.

"More," Mello murmured, pushing Matt up so he was sitting, and seated himself in Matt's lap. He brushed his lips against Matt's before trailing along his jaw to his ear. "I want to feel you more, Matty," he said huskily, letting out that low whistle again.

Matt let out a throaty groan as he felt his member harden fully again. So it was the whistle. He didn't understand how just a mere whistle could do this to him, how it could have this much power over him. However, he figured he could forgive the blond since he was getting sex like this out of it.

Matt was pulled from his reverie when Mello lifted up and impaled himself on Matt. The blond immediately started moving up and down, getting deeper and deeper, searching for the spot he knew would make him see stars. Matt gripped Mello's hips and helped him move as their lips crashed together again.

It was a few minutes of unsuccessful searching before Mello got fed up, pushing Matt to lie down as he adjusted his position atop the redhead. He began to move again, the angle getting much deeper now.

Matt was startled by the sudden change in position, but was enthralled at the sight of the sexy blond riding him. He groaned in pleasure, and decided to help Mello by thrusting up into his downward thrust. They were both rewarded by the intense moan that Mello let out as Matt's cock finally brushed against his prostate.

The rhythm found now, they continued in the same manner, eliciting moans and groans from the both of them, their breaths quickening again.

When Mello felt his climax coming, he pulled Matt back up to him so he could kiss him deeply, hands buried in red hair, keeping Matt from escaping.

One of Matt's own hands wrapped around Mello's back to help him keep the rhythm, while the other drifted between them and took hold of Mello's dripping cock once more.

Mello finally pulled away from Matt's lips when he hit his climax. "Ahh- Matt!"

The redhead groaned at the feeling of Mello's tight hole squeezing him and released into him again, a gasp of pleasure escaping from his swollen lips.

Matt sighed, pulling out of Mello and collapsing backward onto the couch, dragging the blond with him. "That was amazing," he murmured. "You should have been uke, a long time ago."

Mello sent a glare at Matt, but saw the teasing glint in the redheads eyes. "Well, you weren't as cocky back then, nor as big." It was true; Matt had changed from being a helpless puppy to being a confident wolf, plus he had a few inches on him in height and length.

A smug smile spread across Matt's features. "So you're submitting to the fact that you're the uke in this relationship?"

"Hell no!" Mello said in a harsh tone that contradicted how he snuggled in closer to Matt's chest. "We both know the power I have over you."

Matt's hand grabbed Mello's chin and tilted his head up to look Matt in the eye. "Speaking of which, I'd like to know how you did that. I know it has something to do with that whistle."

The redhead was surprised by the sheepish smile Mello made.

"You see," he started, "it all began with Pavlov's dogs, my own experiment, and a _different_ kind of conditional reflex."

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**Wow, that was... that was something. Took me long enough to write it; wasted my whole day. Not that I think it was a waste, I'm just saying I had no other time for anything else. XD**

**I really hope you enjoyed it as much as my first lemon**_**. **_

**I was going to make Mello the seme in this one, but Matt decided to be cocky and top Mello again. I promise the next one will have Mello as the top. I already have the idea for it. I just need to write it.**

**Please R&R and tell me what you thought of it. :D**


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